After pediatrician Dr. Tracy Wilkinson, the lead study author, heard strange information from her teenage patients about emergency contraception, she decided to investigate. She and several researchers called over 940 pharmacies in five cities posing as 17-year-old girls who wanted information about the morning after pill. At the time, emergency contraception was available to all people 17 years and older, so they researchers should have been able to buy it easily on their own.

Instead, they found that some pharmacists incorrectly told them that they had to be accompanied by a parent or guardian to obtain emergency contraception or that an older friend could not buy it for them. Some said they did not stock or dispense it for moral reasons or religious beliefs. There was also some confusion around the rules, with several pharmacists saying the researchers needed to be 18 or have a prescription to buy it.

"About 20 percent of the pharmacy staff said that, because the callers identified themselves as teens, the callers couldn't get it at all. That's completely incorrect," Wilkinson said. "Of the remaining 80 percent of respondents, about half of them got the exact age requirement correct and half of them did not."

This confusion around emergency contraception regulations makes it harder for young women to access it and take it in time for it to be effective. In a fortunate decision this July, the Obama administration made Plan B One-Step available over the counter to all people of all ages with no photo identification required, but other brands have different rules, only adding to some of the confusion. Medical professionals recommend women obtain emergency contraception in advance so they can easily access it when necessary.